DENVER (AP) — Nine people have been indicted by a federal grand jury in Denver as part of a national crackdown on synthetic drugs.

Federal officials said Wednesday that the nine people are from various states and some are also facing state charges. It wasn’t immediately clear whether they have been arrested yet or whether they have lawyers.

Among those indicted is John Gilbert Bowen of Las Vegas. Investigators say he ran a business which sent synthetic drugs to Wisconsin, Nebraska, Alaska, Ohio, Georgia and Illinois as well Colorado.

Synthetic marijuana has been linked to outbreaks of illness in Colorado and elsewhere. While real marijuana is legal in Colorado, synthetic marijuana blends marketed under names such as K2, Spice and Blaze are not.